A. Field of the Invention
This invention relates to image processing systems and more particularly to a system and method for use in such fields as character recognition, the inspection of printed circuit boards, and the image processing of visual robots.
B. Prior Art and Problems to be Solved by the Invention
To perform pattern recognition, it is usually necessary to set a 3.times.3 or 4.times.4 mask on the original image information and execute image information processing. Executing this masking process with a microprocessor is very inefficient, and requires much time because the amount of image information is enormous. Many attempts have been made to increase the efficiency of the masking process by adding hardware, but in no case has a sufficient processing speed been implemented using a comparatively small amount of hardware that can be economically produced. The art has been faced with a dilemma in that when a faster processing speed has been sought, the hardware becomes too large for production, and if the hardware is simply arranged, the processing speed becomes unacceptably slow.
To mask images represented by information that is densely packed in a storage unit in the form of consecutive bits, it is necessary to convert the items of image information in the storage unit to a form representing an original rectangular shaped image that has a length and a width. To accomplish this, the information needs to be re-packed in a storage unit with a length corresponding to the width of the original image. Such a storage unit, which may hold several lines of the image information, is called a line buffer. Line buffers have accordingly been provided with a function for storing image representations of several lines, making it possible to cut the image into rectangles of, for example, 3.times.3, for the masking process. Consequently, various hardware utilities for the masking process have been conceived, and it can be said that the difference in their construction resides in the method of constructing the line buffers. Among these methods are the shift register method and the RAM method. The shift register method representative of the conventional hardware utility operates generally as follows.